Safety device for an operator during the servicing of a hub of a wind turbine

ABSTRACT

A safety device, for ensuring the safety of an operator, is arranged in a rotor, in particular of a wind turbine. The device has a platform with a number of standing surfaces, at least one of the standing surfaces being substantially horizontal when the safety device is used as intended, and also having a securing system for securing the platform to a hub of the rotor and/or to an inner face of a rotor housing of the rotor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International ApplicationNo. PCT/EP2013/056683 filed Mar. 28, 2013, and claims the benefitthereof. The International application claims the benefit of EuropeanApplication No. EP13150842 filed Jan. 10, 2013. All of the applicationsare incorporated by reference herein in their entirety.

FIELD OF INVENTION

The present invention relates to a safety device for ensuring the safetyof an operator for an arrangement in a rotor, more particularly a windturbine. It furthermore relates to a method for ensuring the safety ofan operator for an arrangement in a rotor, more particularly a windturbine.

BACKGROUND OF INVENTION

By “rotors” are meant for example the drive propellers of aircraft,hovercraft and ships as well as also the wind and water wheels servingfor obtaining energy. Wind turbines, more particularly industrial scalewind turbines, have a nacelle which is mounted on a tower, as well as arotor which is mounted on the nacelle. The rotor represents a movablepart of the wind turbine. It is connected by means of a shaft on thedrive train to the interior of the nacelle in which typically thegenerator as well as further electrical and electronic elements arelocated. Within the scope of the invention by “rotor” is understood thecomplete unit of a hub, rotor blades fastened on the hub, and arotatable substantially horizontally lying rotor axis. When the rotor isused as intended the rotor blades drive the hub and the rotor axis andthus the generator.

The rotor of the wind turbine is normally fitted with a plurality ofrotor blades, by way of example two, three or more rotor blades, whichare mounted protruding radially away from the substantially horizontalcentre axis of the rotor. During operation the rotor blades are oftenturned continuously in the wind by means of an adjusting mechanism sothat an optimum energy yield can be obtained from the existing wind.This can be achieved for example by means of a rotation of the nacelle(yaw drive) and/or by means of a blade angle adjustment (pitch drive) ofthe rotor blades.

The rotor represents a highly complex system in which in particularnumerous movable elements such as the rotor blades and the correspondingadjusting mechanism are arranged. It is therefore necessary from time totime to carry out maintenance work and when required even repairs to therotor. In particular, the hub of the rotor, that is a rotatable centrepiece on which the rotor blades are fastened (a hub with a pitch driveis furthermore also termed a “rotor head”, however in the following theterm “hub” is used as the standard form), represents a region in whichit is particularly difficult and risky for the service personnel tooperate. By way of example here bolts which are used to fasten the rotorblades on the hub have to be regularly checked and/or retightened.

The said service works are nowadays normally carried out by a person whois secured by mobile frames and/or safety belts. The service workersthereby have to climb around at a mostly great drop height in the regionof the open hub (i.e. provided with an access to the nacelle) in the endregion of the rotor. Such procedures are very risky and furthermorecomplicated since the service workers have to be secured in the optimumpossible way at all times.

SUMMARY OF INVENTION

Starting from the problem illustrated here an object of the invention isto provide the possibility for an improved safety of an operator forworking in the hub region of a rotor. More particularly importance is tobe placed on a simpler possibility for safety, and/or such safety, whichis equipped with a higher safety standard.

This is achieved by a safety device and by a method according to theindependent claims.

According to this a safety device of the type mentioned at the beginningcomprises at least the following elements: a platform having a pluralityof standing surfaces of which when the safety device is used as intendedat least one lies substantially horizontal, fixing device for fixing theplatform on a hub of the rotor and/or on an inside of a rotor housing ofthe rotor.

The invention offers the user an at least temporarily fixedly installedplatform with several surfaces which are configured and measured so thathe can stand on them on two legs. These surfaces are called “standingsurfaces” within the scope of the invention. According to the inventionin at least one position of the rotor one standing surface of theplatform lies substantially horizontal. This position of the rotor ischaracterised as being specific for the use of the safety device. Ahorizontal surface offers the advantage that it minimizes the danger ofthe user slipping off.

Within the scope of the invention the term “rotor housing” is to meanthe entirety of all the housing segments of the rotor which surround thehub and connecting flanges of rotor blades on the hub. The rotor housingcomprises in particular also a nose or cap, i.e. a hood-like cover ofthe hub against the wind direction.

In order to configure the platform so that an operator can work safelythereon, it is fixed on the hub and/or on the inside of the rotorhousing of the rotor by means of the fixing device. Thus in theinstalled state inside the rotor the platform is a part of the outermostend of the rotor.

A platform of this kind can be attached fixedly or detachably in theregion of the hub of the rotor by means of the fixing device. With asolid fixing the platform is in the end a fixed constituent part of therotor or hub. In the case of a detachable fixing the platform or thesafety device can also be formed as an add-on solution or as a mountableand in turn demountable device. The fixing device can comprise by way ofexample a screw, rivet, bolt or adhesive connection.

By means of the platform which is fixed by the fixing device in theregion of the hub of the rotor, in addition to a usually curved surfaceof the hub a number of standing surfaces are produced which provide theoperator at any time with defined paths and handling regions during theintended use. The maintenance personnel are furthermore clearly betterprotected against a fall from a great height and can operate freely onthe platform, more particularly unimpeded by security harnesses orcorresponding security ropes. Drop paths are shortened since theplatform also functions at the same time as a type of room divider ofthe interior space between the hub and the rotor housing. Overallmaintenance and repair works are thereby easier in the region of the hubof the rotor, by way of example to renew a seal or to inspect andtighten bolts which fasten the rotor blades on the hub.

The invention furthermore comprises a rotor, more particularly a rotorof a wind turbine having a safety device according to the invention aswell as a wind turbine having a safety device according to theinvention.

The invention furthermore comprises a method of the type mentioned atthe beginning wherein at least one standing surface of a platform of thesafety device when the safety device is used as intended is positionedsubstantially horizontal wherein the platform is fixed on a hub of therotor and/or on an inner side of a rotor housing of the rotor.

The method according to the invention can be achieved by means of thesafety device according to the invention.

Further particularly advantageous configurations and developments of theinvention are apparent from the dependent claims as well as from thefollowing description wherein the independent claims of one claimcategory can also be developed analogously to the dependent claims ofanother claim category.

The platform can fundamentally be suspended or mounted floating on thehub or on the rotor housing so that it is aligned each time in theproperly designated position for use. In this case at least one standingsurface of the platform thus always stands horizontal. The platform canhave by way of example a weight which draws it always into thehorizontal position and an additional locking device so that it reliablyremains in this position during maintenance work. According to aconfiguration the safety device is mounted fixed on the hub of the rotorand/or on the inside of the rotor housing. The platform thusautomatically turns during a rotational movement of the rotor or hub andthe rotor housing, i.e. in the right direction and angle. Moreadvantageously standing surfaces of the platform are arranged atdifferent angles to one another so that the safety device provides ahorizontal standing surface not only in the case of one single positionof the rotor.

According to an embodiment of the invention the platform is arrangedrelative to each two connecting flanges of rotor blades on the hub sothat a standing surface on one side of the platform facing the rotorhousing lies substantially parallel to a vertex face of the hub. By“vertex face” is meant a region of the curved surface of the hub whichlies between two adjoining connecting flanges of the hub. With arotation of the hub about the rotor axis the vertex faces arrangedradially around the rotor axis are therefore aligned substantiallyhorizontal alternately on a top side and an underneath side of the hub.“Substantially horizontal” hereby means that the curved vertex facestands symmetrical relative to a substantially flat standing surface. Athree-vane rotor has by way of example three vertex faces.

The maintenance worker normally stands for a particularly long time onthe vertex faces of the hub for example since in the event of asubstantially horizontal alignment these faces represent a safe, becausecomparatively less precipitous, standing site and offer a comfortableaccess to the adjoining connecting flanges of the rotor blades. Asubstantially parallel position of the standing surfaces on the outsidesof the platform relative to the respective corresponding vertex faces ofthe hub has proved particularly favourable since it clearly becomeseasier for the operator to climb from one standing surface to the nextvertex face. This then plays a role particularly when the operator setsup for example a mobile ladder on the standing surface and whereapplicable leans against an end face of the hub and then climbs up theladder in the direction of the vertex face.

The platform of the safety device is advantageously arranged relative tothe main extension directions of the rotor blades of a wind turbine sothat a standing surface always lies substantially horizontal on an outerside of the platform when a rotor blade points downwards along a towerof a wind turbine towards a ground surface. This provides thepossibility that a rotor blade mobile maintenance unit can be movedalong the rotor blade between the hub and a rotor blade tip (for examplefor inspection and maintenance work) and at the same time an operatorcan carry out inspection and/or maintenance work inside the maintenancechamber between the hub and the rotor housing.

The safety device is particularly configured so that the platformdivides a hollow chamber between the hub and the inside of the rotorhousing into essentially at least two hollow chamber regions separatedfrom one another. The rotor housing can stand at such a distance fromthe hub which is measured so that an operator can move by crawling,kneeling or semi-upright therein. The hollow chamber can be formed likea dish and is penetrated by at least three rotor blades which are fittedon the hub. The platform can extend between a surface on the outside ofthe hub and a surface on the inside of the rotor housing. Dividing upthe hollow chamber has proved advantageous since the drop path of anoperator when falling down or sliding down in the hollow chamber alongthe surface of the hub is significantly reduced. It is particularlyadvantageous if the platform is therefore designed so that it dividesthe hollow chamber into a plurality of separated hollow chamber regions.

Basically the platform of the safety device can have any shape, forexample a polygonal or circular configuration. According to anotherembodiment the platform comprises three platform elements each with atleast one standing surface to form a triangle. The platform elements canbe formed circular or angular, e.g. rectangular or square. They can havethe form of a frame, grid or scaffold, and be of the same or differentsize. The platform elements can form a triangle where they are connectedto one another at the ends or at the edges running substantiallyparallel to the rotor axis. A chamber which is enclosed or defined bythe insides of the platform elements directed towards the rotor axis isthus likewise triangular-shaped. It is called a “central chamber” withinthe scope of the invention. The platform elements of the triangle areparticularly dimensioned sufficiently large so that thetriangular-shaped central chamber can shelter an operator, e.g. amaintenance technician.

A triangular shape of the platform offers the advantage that analignment of the standing surfaces can be coordinated particularlysimply with a position of the rotor blades when the rotor of the windturbines has three rotor blades. If the platform is formed as anequilateral triangle, then it can be positioned relative to the hub sothat during a rotor rotation about 120° a change always takes place froma first standing surface in a horizontal position to a second standingsurface in a horizontal position. The platform according to theinvention thus reduces the dependency of the horizontal position of astanding surface on a position of the rotor blades.

Advantageously at least one of the platform elements comprises at leastone opening as access for an operator. It is advantageous if all theplatform elements comprise an opening. The opening(s) can advantageouslyhave a dimension, or in the case of a circular opening, a diameter,which is large enough so that an operator can pass from any hollowchamber region through the opening into another hollow chamber region.The operator can pass from a chamber inside the hub into the hollowchamber between the hub and the rotor housing. He can then step from thechamber first into a region inside the triangular platform, the “centralchamber”. From there the opening according to the invention in one or ineach platform element allows access to one or any further hollow chamberregion, wherein the access leads each time through a hollow chamberregion inside the platform respectively to the “central chamber”.

In principle an opening in the platform element can be openedpermanently during operation of the safety device. In particular thesafety device comprises a closing element for closing the opening. Theclosing element can be a flap, a sliding door, or a roller shutter whichallows an opened and a closed state of the opening. It can also beformed as a removable cover. An operator can cover the opening by meansof the closing element after passing through. The closing element isparticularly designed so that it can be loaded with a weight of theoperator without opening automatically.

The further development according to the invention thus contributes tothe safety of the operator. It reduces the risk of injury if theoperator slides or falls down, for example starting from the vertexface.

According to a configuration of the safety device the platform comprisesbridging elements which span the contact points of the platform elementson the inner sides of the platform elements facing a rotor axis. By“contact point” is meant a place or spatial area where the ends of twoplatform elements meet one another at an angle and are for examplewelded to one another. By “inner sides” of the platform elements aremeant those sides which in the case of a three-dimensional shape of theplatform face one another and at the same time towards the rotor axis.The bridging elements can be set up at any points of the inner sides.They can have the configuration of a frame, grid or scaffold, and can beof the same or different size. They can be fastened on the platformelements by means of screw connections, adhesive connections, bolts orrivets. The bridging elements may each comprise at least one standingsurface on which an operator can stand. When fitting a for exampletriangular-shaped platform with for example three bridging elementsaccording to the invention, at least one doubling of the standingsurfaces on an inside of the platform to six standing surfaces can beachieved by the bridging elements. With a rotation of the rotor around360° an operator can consequently use in six different positions of therotor a horizontal standing surface in an inner hollow chamber region ofthe platform.

The bridging elements can basically each stand at any angle to theplatform elements. The platform elements may stand on their inner sidesfacing the rotor axis at an angle of 120° to inner sides of eachadjoining bridging elements likewise directed to the rotor axis. Whenthe platform is designed as an equilateral triangle it results therefromthat each bridging element stands parallel to each opposite platformelement. Thus with a rotation of a rotor about 120° in a starting and inan end position of the rotational movement, two parallel floors of theplatform i.e. a platform and a bridging element, lie horizontal. Thus byway of example it becomes clearly easier to set up a ladder on abridging element. The ladder can help the operator to pass from a spaceinside the triangular-shaped platform to an opening arranged above same,and then through it to a standing surface of a platform element lyingparallel above same. Consequently during a rotation of the rotor about60° a change takes place from one standing surface to an adjacentstanding surface which then each lie horizontal and offer the operator asafe standing surface. The configuration according to the invention cansignificantly simplify the work of a maintenance technician in thehollow chamber, for example on the connecting flanges of the rotorblades.

In principle the platform can be fastened solely on the hub of therotor. According to a configuration the safety device comprises strutelements as a fixing device which connect the platform at contact pointsof the platform elements to an inner side of the rotor housing. Thestrut elements can be placed at any points on the inside of the rotorhousing. They can have the form of a frame, grid or scaffold, of thesame or different size. Furthermore they can be fastened to the platformor on the inside of the rotor housing by means of screw connections,adhesive connections, bolts or rivets. The strut elements canfurthermore be designed so that they divide the hollow chamber betweenthe hub of the rotor and an inside of the rotor housing into separatehollow chamber regions.

The strut elements can basically be anchored at any points of the rotorhousing which surrounds the hub and connecting flanges of the rotorblades on the hub. They are particularly fastened in the region ofinterfaces of segments of the rotor housing. The strut elements mountedon the platform thus connect the segments of the rotor housing to oneanother. The platform can serve by way of the strut elements as areinforcement element of the rotor housing insofar as through its shapeit absorbs the tensile forces acting on a housing segment of the rotormuch more effectively than an adjacent housing segment. Fastening thestrut elements on interfaces of the housing segments furthermore offersthe advantage that fastening means, for example flat angle plates, areusually already provided at the interfaces which the strut elements canuse for connection. Furthermore a single strut element can thereby befitted at the ends of two housing segments of the rotor and stabilizethem.

The platform is particularly likewise also mounted on the hub so thatthe segments of the rotor housing not only support one another, butultimately are fastened on the hub of the rotor. The strut elements canthereby replace or support any other reinforcement elements whichconnect the hub, a rotor housing as well as a rotor hood, structurallyto one another. The configuration according to the invention thus servesas a structural element of a rotor and stabilises the rotor housingwhich increases its resistance for example to acute wind loads. Thesafety device thus offers a valuable synergy effect.

The strut elements can run substantially parallel to a longitudinal axisof a blade of the rotor between interfaces of segments of the rotorhousing and the platform. The safety device with the elements of theplatform elements, the bridging elements and the strut elements can beconstructed symmetrically, e.g. three-fold radially symmetrically. Sucha design can enhance the working safety of the operator since the safetydevice has the same configuration each time in three different positionsof the rotor. The operator is thus not forced to get used to or adapt todifferent forms and sizes of plates, standing surfaces, openings, whichcan take up part of his attention and in some circumstances can lead toa loss of time or accidents. Rather he discovers a uniformly configuredworking environment.

The platform elements, bridging elements and strut elements canbasically each have a quite different shape. By way of example theplatform elements can be designed flat, whilst the strut elements can onthe other hand be grid-like structures. The platform elements and/or thebridging elements and/or the strut elements are particularly designed asflat plates. The flat plates can be by way of example metal plates, forexample made of corrosion-resistant stainless steel or aluminium.Alternatively they can be made of plastics, e.g. of glass fibrereinforced plastics, of wood or of carbon fibre.

It is advantageous if the platform elements, bridging elements and strutelements are formed solely as plates. They each provide smooth standingsurfaces which guarantee a particularly high working safety by notoffering any engagement points for catching or clamping on an operator,which can lead for example to tripping and falling. The plates accordingto the invention can thereby provide the platform elements, bridgingelements and strut elements with two standing surfaces lying parallel toone another on a front and a rear side.

The plates may extend continuously or substantially without any gapsbetween an outer side of the hub and an inner side of the rotor housingso that they pass through the entire hollow chamber. The plates thusensure that an operator in the event of falling down, for example from avertex face, does not unintentionally pass from one hollow chamberregion into another hollow chamber region or becomes jammed in aninterspace. The same advantage is produced for tools or spare partswhich an operator may be carrying loose with him; should they becomeundesirably lost or dropped they are prevented from slipping throughinto another hollow chamber region and can be quickly found again by theoperator.

Furthermore the plates offer the advantage that they can connect a rotorhood to the hub and can thus additionally strengthen a structure of therotor housing. The plates therefore may have fastening elements forfastening the rotor hood on the platform. The fastening elements cancomprise for example angle plates which are fixed on the plates or therotor hood by means of rivets or screw connections.

According to a configuration of the safety device an extension of theplatform elements in a direction substantially transversely orvertically to the rotor axis comprises at least 1 m, particularly atleast 1.3 m and more particularly at least 1.5 m as well as at most 5 m,particularly at most 4 m and more particularly at most 3 m. Thisextension permits an optimum adaption of the safety device to rotors,more particularly of wind turbines which have a different size and powerperformance.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained below once more in further detailwith reference to the accompanying drawings and using embodiments. Thesame components in the different figures are thereby provided withidentical reference numerals. The drawings show:

FIG. 1 a perspective illustration with a partial section of a rotorhousing according to the prior art;

FIG. 2 a perspective partial section from the right of a rotor housingwith an embodiment of the safety device according to the invention;

FIG. 3 a side view from the right of the rotor of a wind turbine withthe safety device;

FIG. 4 a front view of a rotor housing with the safety device; and

FIG. 5 a diagrammatic front sectional view of a rotor housing with thesafety device.

DETAILED DESCRIPTION OF INVENTION

FIG. 1 shows a section of a rotor 1 of a wind turbine with a hub 3 whichis surrounded by a rotor housing 12. The rotor 1 is formed with threevanes, i.e. it has three rotor blades (not shown in FIG. 1) protrudingradially from the hub 3. Inside the hub 3 there is a tunnel-shapedhollow chamber (not shown) which serves as access from a tower (notshown) or a nacelle (not shown) of a wind turbine to connecting flanges7 of the rotor blades 5 on the hub 3. An exit 9 connects the tunnel to adish-like maintenance chamber 21 between the hub 3 and the rotor housing12. Three two-prong ladder sections 10 protrude from an edge of the exit9. An operator 16, e.g. a maintenance technician, climbs over an upperladder section 10 in the direction of a vertex face 4 of the hub 3. Thevertex face 4 forms a region of the curved surface of the hub 3 whichlies between the two circular connecting flanges 7 of the rotor blades 5of the rotor 1. In the illustrated position of the hub it offers afavourable, because substantially horizontally aligned, standing sitefor the operator 16 in order to inspect or tighten bolts for example bywhich the rotor blades 5 are mounted on the hub 3. According to theprior art an operator 16 can rope himself by means of safety harness orbelts onto security points which lie on an inner side 14 of the rotorhousing 12 and/or on an outer surface of the hub 3 so that the operator16 is protected against sliding or falling down.

FIG. 2 shows a safety device 19 according to the invention on the rotor1. A platform 20 is mounted at the front on the hub 3 of the rotor 1 andis supported by three feet as strut elements 28 or a fixing device onthe inner side 14 of the rotor housing 12. The platform 20 is fixed onthe hub 3 so that it turns automatically during a rotational movement ofthe rotor 1. The rotor housing 12 includes three housing segments 13which enclose the hub 3, the connecting flanges 7 of the rotor blades 5and the platform 20. The rotor housing 12 has a front circular openingwhich during operation of the rotor 1 is covered by a rotor hood (notshown). The strut elements 28 of the platform 20 connect at interfaces17 between the housing segments 13. The platform 20 and the strutelements 28 are made substantially of metal.

The platform 20 has three oblong platform elements 24 of identicallength which are brought together in the form of an equilateraltriangle. The platform elements 24 stand at internal angles α of 60°relative to one another. Each platform element 24 has an extension of 2m in a direction perpendicular to a rotational axis R. At the innersides 34 of the platform elements 24 facing the rotor axis R webs actingas bridging elements 26 span the tips of the triangle, i.e. the seampoints between two adjoining platform elements 24. The tips are formedfrom contact points 25 of the platform elements 24. Each bridgingelement 26 thereby stands at an angle of 120° to an adjacent platformelement 24. Each bridging element 26 thereby also lies parallel to aplatform element 24 which is opposite it on the other side of a centralchamber 23 (as hollow chamber region). The platform elements 24furthermore each have an opening 29 or an aperture which is covered hereeach time by a removable circular cover 30 as a closing element. Thecovers 30 have a diameter b which is large enough so that an operatorcan slip through the opening 29. The platform 20 is measured so that thecentral chamber 23 is large enough so that an operator can stop and moveabout therein.

Whilst the bridging elements 26 offer an operator a standing surface 32for standing up, the platform elements 24 each have two potentialstanding surfaces 32. An inner one of these standing surfaces 32 therebypoints towards the rotor axis R, an outer standing surface 32 pointstowards the rotor housing 12. In the central chamber 23 of the platform20 there are therefore six potential standing surfaces 32. When any onestanding surface 32 is located in a horizontal position each rotation ofthe rotor 1 around 60° causes a horizontal position of an adjacentstanding surface 32.

The strut elements 28 are seated on the outside at the tips of thetriangle of the platform 20. Each strut element 28 extends substantiallyparallel to a longitudinal axis L of an adjacent rotor blade 5. Sincethe strut elements 28 are formed as flat plates they divide togetherwith the platform elements 24 a maintenance chamber 21 between the hub 3and the rotor housing 12 (as hollow chamber) into three outer partialchambers 22 (as hollow chamber regions) and a central chamber 23 (ashollow chamber region), which lies inside the platform 20.

Several angle plates 38 are mounted on the platform elements 24 andfasten the platform 20 on one side on the hub 3 and on the other side onthe rotor hood (not shown).

The platform 20 according to the invention offers the advantage that itsin total nine potential standing surfaces 32 and its openings 29 providean operator with defined paths and handling regions inside a maintenancechamber 21. The triangular design of the platform 20 offers on its outerside during a rotor rotation about 120° a horizontally lying standingsurface 32, and even on its inner side facing the rotor axis R during arotor rotation about 60°. It can thus assist or even replace aconventional safety fitting of an operator, such as safety harness andbelts. The platform 20 furthermore considerably shortens the fall pathsof an operator, e.g. from a vertex face (not shown) of the hub 3starting in the direction of a connecting flange 7 of a rotor blade 5which in this situation points directly downwards. The safety device 19furthermore functions as a structural element of the rotor 1 and servesfor a reinforcement and thus stabilizing of the rotor housing 12 withthe rotor hood (not shown).

FIG. 3 shows, in contrast to FIG. 2, an operator 16, e.g. a maintenancetechnician who is moving forwards in an outer partial chamber 22 on acurved surface of the hub 3 in the direction of a vertex face 4 of thehub 3. A horizontally aligned platform element 24 as well as the strutelements 28 which adjoin the ends of the platform element 24 and runinclined relative to the platform element 24 close off an upper outerpartial chamber 22 from further partial chambers 22, 23. A fall path ofthe operator and his equipment, e.g. loosely carried spare parts and/ortools, is thereby clearly shortened. A continuous extension of theplatform elements 24 and the strut elements 28 between the hub 3 and therotor housing 12 reliably prevents the operator and smaller elementsfrom becoming jammed or slipping through.

FIG. 4 shows, in contrast to FIGS. 2 and 3, the safety device 19according to the invention in a front view. The operator 16 standsfacing the viewer on a horizontal standing surface 32 of a bridgingelement 26 and has in front of him a mobile ladder 40 which is likewisestanding on the bridging element 26. A spacing between the bridgingelement 26 and the platform element 24 is here greater than a body sizeof the operator 16. The mobile ladder 40 extends up to an open opening29. The operator 16 when climbing up the ladder 40 can pass through theopening 29. He can then move on a horizontal standing surface 32 of theplatform element 24. An opening of the rotor housing 12 released by thehousing segments 13 is covered by a disc-like rotor hood 15. Theplatform elements 24 have angle plates 38 which run along an extensionof the platform elements 24 between the strut elements 28, and fastenthe platform 20 additionally on the hub 3.

FIG. 5 shows, in contrast to FIG. 4, more particularly the three-foldradially symmetrical construction of the safety device 19 according tothe invention. Each of the three strut elements 28 aligns flush with alongitudinal axis L of one of the three rotor blades 5 or standsparallel to it. The platform 20 with its platform elements 24 forms anequilateral triangle. A longitudinal axis L of each rotor blade 5 standsperpendicular to an opposing platform element 24. The strut elements 28are mounted by means of bolts 18 as fixing device on interfaces 17 ofthe segments 13 of the rotor housing 12.

It is finally pointed out once more that the devices described in detailabove are only examples of embodiments which can be modified by oneskilled in the art in the most varied of ways without departing from thescope of the invention. Furthermore the use of the indefinite article“a” and “an” does not rule out that the relevant features can also bepresent in several numbers.

1. A safety device for the safety of an operator in a rotor, comprisinga platform having a number of standing surfaces of which when the safetydevice is used as intended at least one standing surface liessubstantially horizontal, fixing device for fixing the platform on a hubof the rotor and/or on an inner side of a rotor housing of the rotor. 2.The safety device according to claim 1 wherein the safety device ismounted fixed on the hub of the rotor and/or on the inner side of therotor housing.
 3. The safety device according to claim 1 wherein theplatform is arranged relative to each two connecting flanges of therotor blades on the hub so that a standing surface on a side of theplatform facing the rotor housing lies substantially parallel to anvertex face of the hub.
 4. The safety device according to claim 1wherein the platform divides a hollow chamber between the hub and theinner side of the rotor housing into substantially at least two hollowchamber regions separated from one another.
 5. The safety deviceaccording to claim 1 wherein the platform comprises three platformelements each with at least one standing surface which form a triangle.6. The safety device according to claim 5 wherein at least one of theplatform elements has at least one opening as access for an operator. 7.The safety device according to claim 5 wherein the platform comprisesbridging elements which span the contact points of the platform elementsat the respective inner sides of the platform elements facing a rotoraxis (R).
 8. The safety device according to claim 7 wherein the platformelements stand at their inner sides facing the rotor axis (R) at anangle (β) of 120° to the inner sides of the respective adjoiningbridging elements which are likewise directed towards the rotor axis(R).
 9. The safety device according to claim 5 wherein the fixing devicecomprises strut elements which connect the platform at the contactpoints of the platform elements to the inner side of the rotor housing.10. The safety device according to claim 9 wherein the strut elementsare fastened in the region of interfaces of segments of the rotorhousing.
 11. The safety device according to claim 9, further comprisingflat plates as platform elements and/or bridging elements and/or strutelements.
 12. The safety device according to claim 5 wherein anextension (a) of the platform elements transversely to the rotor axis(R) comprises at least 1 m, as well as at most 5 m.
 13. A rotor with asafety device according to claim
 1. 14. A wind turbine with a safetydevice according to claim
 1. 15. A method for securing an operator witha safety device in a rotor the method comprising: positioning at leastone standing surface of a platform of the safety device, when the safetydevice is used as intended, substantially horizontally wherein theplatform is fixed on a hub of the rotor and/or on an inner side of arotor housing of the rotor.
 16. The safety device according to claim 1,wherein the safety device is adapted for a wind turbine.
 17. The safetydevice according to claim 6, wherein at least one of the platformelements has at least one closing element for closing the opening. 18.The safety device according to claim 12, wherein the extension (a) ofthe platform elements transversely to the rotor axis (R) comprises atleast 1.3 m, as well as at most 4 m.
 19. The safety device according toclaim 12, wherein the extension (a) of the platform elementstransversely to the rotor axis (R) comprises at least 1.5 m, as well asat most 3 m.